Department of Ophthalmology, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Hirokoji-agaru, Kawaramachi-dori, Kamigyo-ku, Kyoto, 602-0841, Japan.
Department of Frontier Medical Science and Technology for Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Exp Eye Res. 2021 Apr;205:108496. doi: 10.1016/j.exer.2021.108496. Epub 2021 Feb 19.
The aim of the study is to clarify the participation of extracellular vesicles (EV) secreted by murine primary retinal pigment epithelial (mpRPE) cells in the cell to cell communication with macrophages (Mps), firstly described by the authors in 2016. In ocular inflammation, Mps act as sources of tumor necrosis factor-α (TNF-α), an activator of RPE cells. TNF-α stimulates the production of monocyte chemotactic protein (MCP-1) by RPE cells, thereby causing greater recruitment of Mps to the sub-RPE space. Murine RAW 264.7 Mps cells were co-cultured with C57BL/6 mouse mpRPE cells, either together or separated in transwells, vertically or horizontally connectable, with 0.40 or 0.03 μm membrane filters. The association of EV with mpRPE or RAW 264.7 was quantified by fluorescence cell sorting (FACS) using Qdot655 streptavidin-conjugated biotinylated EV. Increased levels of CD63 EV were detected in co-cultures by western blotting or FACS analysis, in accordance with the increased production of nanoparticles (50-150 nm) detected by Nanosight tracking analysis. The gene expressions of cytokines, MCP-1, IL-6, IL-8, and VEGF in mpRPE cells and the corresponding proteins were increased in co-cultures even in transwells, vertically connected with 0.40 μm membrane filters, while the repressed TNF-α protein production was not affected. Most of the CD63 EVs produced by mpRPE cells in co-cultures were associated with Raw264.7, but not with mpRPE cells. Semi-purified CD63 EV secreted from mpRPE cells, increased the secretion of MCP-1, IL-6, and VEGF in co-cultures with RAW 264.7. Culture chamber separation horizontally connected with 0.03 μm membrane filters reduced this increased secretion. Collectively, mpRPE derived CD63 EV partly participate in the sub-retinal innate inflammation. To evaluate the functional damage of RPE cells upon chronic exposure to here defined EVs will be the critical issue to uncover their roles in chronic retinal degenerative diseases.
本研究旨在阐明 2016 年作者首次描述的鼠源原代视网膜色素上皮 (mpRPE) 细胞分泌的细胞外囊泡 (EV) 在细胞与巨噬细胞 (Mps) 之间的细胞通讯中的作用。在眼部炎症中,Mps 作为肿瘤坏死因子-α (TNF-α) 的来源,TNF-α 可激活 RPE 细胞。TNF-α 刺激 RPE 细胞产生单核细胞趋化蛋白-1 (MCP-1),从而导致更多的 Mps 募集到 RPE 下腔。将 C57BL/6 鼠源 mpRPE 细胞与鼠源 RAW 264.7 Mps 细胞共培养,或共培养于垂直或水平连接的 Transwell 培养板中,膜滤器孔径为 0.40 或 0.03μm。通过使用 Qdot655 链霉亲和素结合生物素化 EV 的荧光细胞分选 (FACS) 定量分析 EV 与 mpRPE 或 RAW 264.7 的结合。Western blot 或 FACS 分析显示共培养物中 CD63 EV 水平增加,纳米粒子 (50-150nm) 的跟踪分析显示纳米粒子产量增加。mpRPE 细胞中细胞因子、MCP-1、IL-6、IL-8 和 VEGF 的基因表达以及共培养物中的相应蛋白增加,即使在垂直连接、膜滤器孔径为 0.40μm 的 Transwell 培养板中也是如此,而受抑制的 TNF-α 蛋白产生不受影响。mpRPE 细胞在共培养物中产生的大多数 CD63 EV 与 Raw264.7 相关,而与 mpRPE 细胞无关。从 mpRPE 细胞中半纯化的 CD63 EV 增加了与 RAW 264.7 共培养物中 MCP-1、IL-6 和 VEGF 的分泌。水平连接的 0.03μm 膜滤器培养室分隔降低了这种分泌增加。总之,mpRPE 衍生的 CD63 EV 部分参与了视网膜下先天炎症。评估 RPE 细胞在慢性暴露于本文定义的 EV 下的功能损伤将是揭示其在慢性视网膜退行性疾病中作用的关键问题。